BOEING is a trademark of Boeing Management Company. Copyright © 2004 Boeing. All rights reserved. BOEING LIMITED Boeing’s Morphing Aerostructures F. Tad Calkins Boeing Commercial Airplanes Enabling Technology and Research Aeroacoustics 425 237-2831 [email protected]

Boeing’s Morphing Aerostructures

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Page 1: Boeing’s Morphing Aerostructures

BOEING is a trademark of Boeing Management Company.Copyright © 2004 Boeing. All rights reserved.


Boeing’s Morphing Aerostructures

F. Tad CalkinsBoeing Commercial AirplanesEnabling Technology and Research Aeroacoustics425 [email protected]

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OutlineMorphing structures Actuation capabilityPotential applicationsThe Future

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Morphing Overview

• Morphing Technologies increase a system’s performance by manipulating characteristics to better match the system state to the operating conditions (environment and task)

• Aerospace applications• Landing gear• Flaps• Swing wing F-14, B1B• Concorde nose tilt• V22 Rotors rotate down

• Active Aeroelastic Wing• Mission Adaptive Wing

V22 Osprey

Land gear



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What’s New

• Current “morphing” has disadvantages• Even small structural changes are difficult• Requires heavy motors, hydraulics, structural reinforcement• Complexity• Expensive

• “Smart” materials lead to new morphing concepts• Fully integrated, distributed actuation• Conventional components given additional capability• Does NOT add weight• Simple mechanisms• Add additional capability to current structure: “multi-

functional element”• Smart materials applicable to morphing structures

– Piezoelectrics, electrostrictives, piezopolymers (electro elastic)– Magnetostrictives, ferromagnetic SMA (magneto elastic)– Shape memory alloys, polymers (thermal elastic)

• Applicability to real airplanes in the near term

Integration of Shape Memory Alloys into aerospace materials, such as composites

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BCA Noise EngineeringAdvantages To Boeing

• Lighter Weight Aircraft• Aircraft that Adapt to Changing Flight Conditions• Low Part Count• Long Shelf Live• Increased Range• Increased Payload• Reduced Noise• Reduced Operating Cost• Reduced Time to Repair or Reconfigure


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Shape Memory Alloy Actuators

• Nickel Titanium based (60-Nitinol, 55-Nitinol, High temp)

• High efficiency, low weight, high energy density

• Shape Memory Effect• Thermally activated• Microstructural phase

change produces shape change under load

• Shape change – Austenite (C) fully

immersed– Martensite (A) retracted

–Thermal management key to actuator operation







in, S





Martensite Transition Austenite


–Other properties of interest–Damping–Superelasticity–Hardness


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Rotary Actuator Characteristics


0 1 2 3 4 5

Log Torque, [N-m]



ent o

f Ine






), [k



DC Motor

AC Winding AC Cage

Radial Piston Hydraulics

Vane Type Hydraulics

Axial Piston


Gear Type Hydraulics

RRB #1

• SMA Actuator Technology benefits• Robust Technology• Lightweight• Integrates well• Simple system design• Flight tested system

• Boeing is world leaders in this technology

Conclusion:• NiTinol is ideal for torque high stroke, low duty cycle applications where weight is a premium• Technology can provide major benefits for aerospace applications

Benefits of SMA Based Design

SMA Rotary Actuator :150 in-lbs

1 lbs

Motor: Torque 66 in-lbs

25 lbs

Gear box :190 in-lbs16 lbs

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• Variable Geometry Chevron• Reconfigurable Rotor Blade• Deployable Rotor Tab• Variable Engine Inlet

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Variable Geometry Chevrons

• Reconfigurable engine nozzle fan chevron

• Apply morphing structures technology to enable efficient chevron shape change

• Shape Memory Alloy is key technology

• Example of new testing capability

• Mature technology TRL level 6-7

Calkins, 2006

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• Goal: morph chevron shape to optimize engine performance

• Community noise reduction• Shockcell noise reduction• Cruise performance

• VGC Program Milestones• Boeing VGC patent application 2002• Concept developed and tested 2002-2005• Flight test on 777-300ER, GE 115B engine

2005• Demonstrated

• Successful flight test– Autonomous Operation – community noise

reduction without cruise losses – Powered Mode – Active design tool

• Potential of VGC Technology


Variable Geometry Chevron Overview

Cruise Position

Take offPosition

Variable Immersion


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Wires routed through conduit in honeycomb core of

inner sleeve.

Inner Sleeve

Outer Sleeve Joined to Inner Sleeve, wiring

routed in space between sleeves

VGC was integrated into production design and fabrication processes. Future applications also need look ahead to system level integration

issues and wherever possible also use a multi-function approach. Mabe, 2006

Improved System Integration

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VGC Flight Test/Static Engine Test Overview

• Instrumentation, power, gages, and controller worked without failure

• Demonstrated autonomous (non-powered) operation

• Demonstrate and tested individual VGC control of 9 Chevron configurations.

Flight Tests

Flight Test used for development of 787 static fan chevrons

Static Engine Test

SMA Actuators Re-engineered for ground based operation.

• Higher Transition Temperature• Increased Authority

• Noise performance evaluated • Demonstrated full autonomous operation

Calkins, 2006, 2007

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BCA Noise EngineeringSMA Actuator Development

Torque Tube Actuator

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Reconfigurable Rotor Blade (RRB)

•Blade Twist Change Enhances Aircraft Performance• Entire System weighs < 20 lbs• 5000 in-lbs twists blade 2 deg

•¼ Scale Wind Tunnel Tests Completed• Integrated 3 actuators into CDI-V8 Blades• Tested blades in several hovering and axial flight configurations• Demonstrated ability of RRB actuation system to morph blade• Twist in a rotating environment


Passive Torque Tube

Shape Memory Alloy ActuatorLocated Within Blade Structure

Heat Rejection System(Blade Upper Surface)

Nano-Composite Leading Edge Erosion Strip(Reduces Blade Weight & Improves protection)

Ruggeri, 2008

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Active Hinge Pin Actuator (AHPA)• Order of magnitude reduction in weight

than conventional actuation devices• Compact size to fit rotor blade profile• Ruggedized for harsh rotor blade

environment• Fails closed on loss of power

Deployable Tabs for Blade Vortex Interaction Noises Reduction

• Blade Vortex Interaction (BVI) noise caused by trailing rotor blades impacting vortices created by leading blade during descent.

• Deployable tabs or flaps break up vortices and significantly reduce noise.

• Conventional actuators too large and heavy.

Mabe, 2008

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Integration is Key to Application Success




MD530F Selected As Target Blade




MD530F Selected As Target Blade




MD530F Selected As Target Blade

Conventional flap Double Acting Hinge

Centrifuge laser dataPIV data

• Centrifuge and wind tunnel testing of deployable rotor blade devices using SMA actuators.

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Engine Inlet Duct Shaping


ρ = 11°

Integrated CMT/SMA Rods

CMT elastomernot shown

Adaptive inlet improves performance over a range of

flight conditions* SMA = Shape Memory Alloy,CMT = Conformal Moldline TechnologySAMPSON = Smart Aircraft and Marine

Projects Demonstration

High Force/DispAntagonist SMA

Tendon Cowl Actuator

Pitt, 2001

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SMA Morphing Structures Design Map

• SMA high energy density, low weight• Simple design, low part count• Fully integrate actuation into existing structure• Add morphing to structural element: use morphing

capability to optimize at multiple conditions• Fast deployment, slower cycling• Autonomous operation, thermal actuation, requires

little or no power

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Composite Design Approaches

• Traditional composite• Stiff, lightweight• Structural

• Multifunctional composite

• Includes other capability (sensing, imbedded electronics)

• Morphing composite• Tailored composite

enables motion/shape change

Integral Substrate

Bonded Acoustic Panel

Power & Instrumentation Conduit


Integral Substrate

Bonded Acoustic Panel

Power & Instrumentation Conduit


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Morphing Structure Needs

• Tools• Modeling of structure and

actuator• Improved design and

analysis tool (FEA based)• Optimization methods• State of the art testing

methods• Integration

• Fully integrated: multi-functional elements

• Active structural element design

• Sensing• Fabrication methods

• Composites• High performance

composites designed for morphing

• Reliability

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SMA Based Morphing Structure Future Direction

• Use technology to explore optimization of at multiple flight/operating conditions

• Incorporate more smart material capabilities into structure

• Realization of true morphing structures that provide distributed continuous optimization of aircraft performance

• Changes design philosophy: design for optimum performance at each condition of interest

• Autonomous operation• Explore morphing technology use for future

“active” design work

• SMA Technology direction• New Alloys (high temperature)• Connections • Fabrication technology

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• Technologists goal is to exploit the right technology for an application to meet a Boeing need.

• Rapid cutting edge technology development • Full scale flight test validates SMA technology, system approach,

and technical readiness for morphing structures.• Current applications provide roadmap for future development.• Factors converging to make this the right time to exploit next

generation morphing structures– SMA technology is ready– Resources are in place – Need is there

• Composites are needed to facilitate morphing aerostructures

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•Questions, Comments ?

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1. F. Calkins, G. Butler, and J. Mabe, “Variable Geometry Chevrons for Jet Noise Reduction”,AIAA-2006-2546, 12th AIAA/CEAS Aeroacoustics Conference, Cambridge MA, May 2006.

2. J.H. Mabe, F.T. Calkins, G.W. Butler, “Boeing’s Variable Geometry Chevron: Morphing aerostructure for jet noise reduction,” 47nd AIAA Adaptive Structures Conference, AIAA-2006-2142, Newport RI, May 2006.

3. Robert T. Ruggeri, Richard C. Bussom, Darin J. Arbogast, “Development of a ¼-scale NiTinol actuator for reconfigurablestructures” SPIE Smart Materials and Structures, 2008, paper 6930-21.

4. D. M. Pitt, J. P. Dunne, E. V. White, “SAMPSON smart inlet SMA powered adaptive lip design and static test”, AIAA-2001-1359,AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, 42nd, Seattle, WA, Apr. 16-19, 2001.

5. Mabe, Gravatt Bushnell, Gutmark, Dimicco, Harris, “Shape Memory Alloy actuator for deployable rotor blade aerodynamic device,” AIAA 2008-1451.